diff --git a/manifest b/manifest
index fc2c9c65f3..6a813187af 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\swith\scheckpointing\slarge\slog\sfiles\screated\sby\san\sexternal\sprocess.
-D 2010-05-07T06:59:09
+C Test\sanother\sIO\serror\scase\sin\swal.c.
+D 2010-05-07T09:43:50
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -207,7 +207,7 @@ F src/test_schema.c 8c06ef9ddb240c7a0fcd31bc221a6a2aade58bf0
 F src/test_server.c bbba05c144b5fc4b52ff650a4328027b3fa5fcc6
 F src/test_tclvar.c f4dc67d5f780707210d6bb0eb6016a431c04c7fa
 F src/test_thread.c aa9919c885a1fe53eafc73492f0898ee6c0a0726
-F src/test_vfs.c 72b8ad1a6bc6c27d9e5b4362d6320d3834c87db6
+F src/test_vfs.c c1e13b5f787042130878996f31827ffb5d4d8efc
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/tokenize.c 25ceb0f0a746ea1d0f9553787f3f0a56853cfaeb
 F src/trigger.c 8927588cb9e6d47f933b53bfe74200fbb504100d
@@ -224,7 +224,7 @@ F src/vdbeblob.c 5327132a42a91e8b7acfb60b9d2c3b1c5c863e0e
 F src/vdbemem.c 2a82f455f6ca6f78b59fb312f96054c04ae0ead1
 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2
 F src/vtab.c a0f8a40274e4261696ef57aa806de2776ab72cda
-F src/wal.c 5321afde90f0819655040d1ca477f3fec9ebefbe
+F src/wal.c 53b7461586bd883313e8bed46830557c720899c8
 F src/wal.h b4c42014b5fa3b4e6244ac8c65de7ff67adeb27c
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
 F src/where.c 75fee9e255b62f773fcadd1d1f25b6f63ac7a356
@@ -765,7 +765,7 @@ F test/wal.test 45fd4e9e8f871f38c801fecbf341528710edbfe1
 F test/wal2.test 0f53c711d6530d3c7aba46752aef9fd44b708c6c
 F test/walbak.test a0e45187c7d8928df035dfea29b99b016b21ca3c
 F test/walcrash.test f6d5fb2bb108876f04848720a488065d9deef69f
-F test/walfault.test ae37204f4375e0e5eba75094d0d0db7148de70a8
+F test/walfault.test bff34172bc224360d9c0d6c7b94454817c8def9d
 F test/walhook.test a1c375ae791d5d7d511c166159729230791c574d
 F test/walmode.test bac6f06544a8554588a1543def996bbe2fc41792
 F test/walslow.test d21625e2e99e11c032ce949e8a94661576548933
@@ -813,7 +813,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 061a282cc0bf76541ab1f99b351a49d489ff93ec
-R 3e2d9c06dafc1b5b325ac114ce5c4263
+P 8f94bde568be52ecc5a976b7a09776ea7b4bb511
+R 33b989a7a16e1f991ebc72039614fbc6
 U dan
-Z a88a95664c9a9b9b2d9abf67515be3e6
+Z e205369239a9a134e8a3ad914124f7a7
diff --git a/manifest.uuid b/manifest.uuid
index 9ba8568eae..f2730afb01 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8f94bde568be52ecc5a976b7a09776ea7b4bb511
\ No newline at end of file
+8b3b5ab8fa61ca4ef22c98abaab397707ee74ea3
\ No newline at end of file
diff --git a/src/test_vfs.c b/src/test_vfs.c
index 76858341cb..1b5b4b09d2 100644
--- a/src/test_vfs.c
+++ b/src/test_vfs.c
@@ -490,12 +490,12 @@ static int tvfsShmGet(
   Testvfs *p = (Testvfs *)(pVfs->pAppData);
   TestvfsShm *pShm = (TestvfsShm *)pShmHandle;
 
-  tvfsGrowBuffer(pShm, reqMapSize, pMapSize);
   tvfsExecTcl(p, "xShmGet", 
       Tcl_NewStringObj(pShm->pBuffer->zFile, -1), pShm->id, 0
   );
   tvfsResultCode(p, &rc);
   if( rc==SQLITE_OK ){
+    tvfsGrowBuffer(pShm, reqMapSize, pMapSize);
     *pp = pShm->pBuffer->a;
   }
   return rc;
diff --git a/src/wal.c b/src/wal.c
index 2f2b53fa7f..ca5fc4e79f 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -411,7 +411,9 @@ static int walIndexMap(Wal *pWal, int reqSize){
       assert( pWal->szWIndex==0 );
       pWal->pWiData = &pWal->iCallback;
     }
-    assert( rc==SQLITE_OK || pWal->pWiData==0 );
+    if( rc!=SQLITE_OK ){
+      walIndexUnmap(pWal);
+    }
   }
   return rc;
 }
@@ -1129,7 +1131,7 @@ int sqlite3WalWriteLock(Wal *pWal, int op){
         walSetLock(pWal, SQLITE_SHM_READ);
       }
     }
-  }else if( pWal->lockState==SQLITE_SHM_WRITE ){
+  }else if( ALWAYS( pWal->lockState==SQLITE_SHM_WRITE ) ){
     rc = walSetLock(pWal, SQLITE_SHM_READ);
   }
   return rc;
diff --git a/test/walfault.test b/test/walfault.test
index dedccf236d..aa8a4ef91b 100644
--- a/test/walfault.test
+++ b/test/walfault.test
@@ -250,5 +250,81 @@ do_shmfault_test walfault-shm-5 -coverageonly 1 -sqlprep {
   ROLLBACK;
 }
 
+#-------------------------------------------------------------------------
+# When a database is checkpointed, SQLite does the following:
+#
+#   1. xShmLock(CHECKPOINT) to lock the WAL.
+#   2. xShmGet(-1) to get a mapping to read the wal-index header.
+#   3. If the mapping obtained in (2) is not large enough to cover the
+#      entire wal-index, call xShmGet(nReq) to get a larger mapping.
+#   4. Do the checkpoint.
+#   5. Release the lock and mapping.
+#
+# This test case tests the outcome of an IO error in step 2.
+#
+proc shmfault_vfs_cb_6 {method args} {
+  switch -- $::shm_state {
+    0 { return SQLITE_OK }
+    1 {
+      if {$method == "xShmGet"} {
+        set ::wal_index [tvfs shm [lindex $args 0]]
+        tvfs shm [lindex $args 0] [string range $::wal_index 0 65535]
+        set ::shm_state 2
+      }
+    }
+    2 {
+      if {$method == "xShmGet"} {
+        tvfs shm [lindex $args 0] $::wal_index
+        return SQLITE_IOERR
+      }
+    }
+  }
+  return SQLITE_OK
+}
+do_test walfault-shm-6.1 {
+  set ::shm_state 0
+  testvfs tvfs shmfault_vfs_cb_6
+
+  sqlite3 db  test.db -vfs tvfs
+  sqlite3 db2 test.db -vfs tvfs
+
+  execsql {
+    PRAGMA journal_mode = WAL;
+    PRAGMA wal_autocheckpoint = 0;
+    CREATE TABLE t1(x);
+    INSERT INTO t1 VALUES(randomblob(900));
+  }
+} {wal 0}
+do_test walfault-shm-6.2 {
+  execsql {
+    PRAGMA wal_autocheckpoint = 0;
+    BEGIN;
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 2 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 4 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 8 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 16 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 32 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 64 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 128 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 256 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 512 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 1024 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 2048 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 4096 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 8192 */
+      INSERT INTO t1 SELECT randomblob(900) FROM t1;    /* 16384 */
+    COMMIT;
+  } db2
+} {0}
+do_test walfault-shm-6.3 {
+  set ::shm_state 1
+  catchsql { PRAGMA wal_checkpoint } db2
+} {1 {disk I/O error}}
+set ::shm_state 0
+db close
+db2 close
+tvfs delete
+unset -nocomplain ::wal_index ::shm_state
+
 finish_test